BERKELEY, CA (UroToday.com) - Historically, after the invention of transrectal ultrasonography, the prostate biopsy (PBx) was first standardized as transrectal sextant biopsy.[1]
Thereafter, multi-core, systematic prostate biopsy was developed to overcome the insufficient diagnostic power of the sextant biopsy and has been widely adopted.[2, 3] We developed a three-dimensional (3D), 26-core (3D26PBx; transperineal 14-core plus transrectal 12-core biopsy) method and have reported its excellent diagnostic performance elsewhere.[4, 5] When we analyzed accumulating clinical data obtained through the 3D26PBx, we found that the diagnostic performance plateaued beyond a certain number of biopsy cores. Therefore, we developed a 3D, 14-core prostate biopsy (3D14PBx; transperineal 8-core plus transrectal 6-core biopsy), eliminating 12 redundant biopsy cores from the 3D26PBx while maintaining a cancer detection rate of not less than 95% of that obtained with the 3D26PBx method.[5, 6] This prospective study confirmed the efficacy and safety of the 3D14PBx method following its application in more than 1 000 men.

Between December 2005 and August 2010, 1 103 men with elevated prostate specific antigen (PSA) (2.5–20 ng/mL) levels or abnormal digital rectal examination (DRE) findings, or both, underwent 3D14PBx at our institutions. Prostate cancer was detected in 503 of the 1 103 patients (45.6%). Age, family history of prostate cancer, DRE, PSA, %-free PSA, and prostate volume were significantly and independently associated with positive biopsy results. Of the 503 cancers detected, 39 (7.8%) were clinically locally advanced (cT3a or greater), and 348 (69%) had a biopsy Gleason score (GS) of ≥ 7. If the cancers were classified as biopsy-based significant cancers when the biopsy GS was ≥ 4+3, positive cores were greater than 50%, the maximum cancer occupation was greater than 50%, and/or the PSA density was greater than 0.15, 463 (92%) met the definition of being biopsy-based significant cancers. Among the 503 patients with cancers, 210 (42%) underwent radical prostatectomy, indicating that 55 (26%) had pathologically non-organ-confined disease and 174 (83%) had prostatectomy GS ≥ 7. If the cancers were classified as prostatectomy-based significant cancers when the GS was ≥ 4+3, the total tumor volume was ≥ 0.5 cm3, and/or extraprostatic extension was observed, 185 (88%) met the definition of prostatectomy-based significant cancers. These diagnostic data following 3D14PBx were satisfactory.

We previously found that there was an intermingled complementarity among the 3D26PBx sampling sites (transperineal and transrectal).[5, 6] Similarly, we found complementarity among the 3D14PBx sampling sites. Recursive partitioning analysis revealed that each sampling site contributed uniquely to both the overall and the biopsy-based significant cancer detection rate of the 3D14PBx method.

Additionally, we confirmed that this biopsy method was sufficiently safe. Major biopsy-related complications requiring prolonged hospital stays or re-hospitalization during the 4-week post-biopsy period were observed in 10 of the 1 103 men (0.9%), including five with acute bacterial prostatitis, two with urinary retention, two with rectal bleeding, and one with urethral bleeding. There were no biopsy-related deaths.

Our newly developed local anesthetic technique[7] enabled us to perform 473 of the 1 103 3D14PBx under local anesthesia; this is a significant advancement in clinical practice. We also confirmed that there was no difference in cancer detection rates between anesthetic methods. When stratified by anesthetic methods, the overall cancer detection rate was 43.4% (259/597) in patients under general anesthesia, 42.4% (14/33) in those with spinal anesthesia, and 48.6% (230/473) in those with local anesthesia.

As to detection of clinically significant prostate cancer, promising results have been reported using multi-parametric magnetic resonance imaging (mp-MRI). Mp-MRI can achieve an excellent negative predictive value and a moderate positive predictive value for significant cancers;[8] therefore, mp-MRI is expected to result in few missed significant cancers. This MRI-guided biopsy technique also appears to be a very promising method for accurately sampling the MRI target.[9] If treatment for mp-MRI-visible prostate cancer is necessary and sufficient, the current treatment strategy for prostate cancer may dramatically change in the near future, similar to kidney cancer where considerable emphasis is now placed on imaging study results. However, mp-MRI remains costly and technically demanding when applied to daily clinical practice. Therefore, at present, we cannot abandon systematic prostate biopsies in daily practice, and we propose that our simple, effective systematic prostate biopsy method is clinically useful.

Written by:Hideki Takeshita, MD, PhD and Satoru Kawakami, MD, PhD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Free Daily and Weekly newsletters offered by content of interest

The fields of GU Oncology and Urology are rapidly advancing. Sign up today for articles, videos, conference highlights and abstracts from peer-review publications by disease and condition delivered to your inbox and read on the go.